1. Field of the Invention
The present invention relates to photoelectric conversion devices.
2. Description of the Related Art
In recent years, photoelectric conversion devices that do not produce carbon dioxide during power generation have attracted attention as a measure against global warming. As typical examples thereof solar cells have been known which use crystalline silicon substrates such as single crystalline and polycrystalline silicon substrates.
In solar cells using a crystalline silicon substrate, a structure having a so-called homo junction is widely used. In such a structure, a layer having a conductivity type opposite to that of the crystalline silicon substrate is formed on one surface side of the crystalline silicon substrate by diffusion of impurities.
Alternatively, a structure with a heterojunction is known in which amorphous silicon having different optical band gap and conductivity type from those of a crystalline silicon substrate is formed on one surface side of the crystalline silicon substrate (see Patent Documents 1 and 2).